Grinding machine



l. M. w. HANsoN. GRIDING MACHINE.

APPLICATION FILED J ULY3I| |918.

l Patented May 16, 1922.

im BI' B.' M. W.-HANSON.

GmNmNG MACHINE.

APPLICATION FILED-JULYH, 1918.

Patented May 16, 1922f Il SHEETS-SHEET 2.

A OBA/EV GRINDING MACHINE.

APPLICATION FILED JULYSI. 1918. 1,416,463. Patented May 16,1922.

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B. IvI. wQHANsoN.

@BINDING MACHINE'.

APgLIcAIIoN FILED IuLvaI. 191s.

Patented May 16, 1922.

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f3 56 )if Y JUVE-N70 BWI Wip/QV "940 A UHNEY B. M. W. HANSON. GRINDING MACHINE. APPLICATION FILED IuLYsI, I9I8.

Patented May 16, 1922.

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` l/VVENTR M. MK [www ,4 OBNEY B. M. w. H ANsoN. GRINDING MACHINE.

APPLICATION FILED IIILY3II I9I8.

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APPLlcATIoN min musi. 191s.

1,416,463, Patented May 16, 1922.

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INVENTOH M. W. [hun gi/75M ,4 rofwfr B. M. W. HANSON.

GRINDING MACHINE.

APPLICATION FILED IuLYsI. I9Ia.

1,416,463, Patented lMay 16, 1922.

Il SHEETSSHEET l0.

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7%/ ,M By A RNEY B. M. W'. HANSON.

GRINDING MACHINE.-

APPLICATION FILED JULYSM 1918. l 1 ,416,463. Patented May 16, 1922.

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MoH/viv different diameters at different'points.

PATENT OFFICE.

UNITED STA'ILS BENG'T M. W. HANSON, 0F HARTFORD, CONNECTICUT, 11S-SIGNOR TO PRATT & WHITNEY COMPANY, OF NEW YORK, N. Y., A GORPORATIQN 0F' NEW JERSEY.

GRINDING MACHIN E.

Application filed July 31, 1918.

To all whom t may concern.'

Be it known that l, Bianca M. W. HANSON, a citizen of the United States, residing at Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Grinding Machines` of which the following is a specification.

The invention relates to grinding machines of the type set forth in my copending application for grinding machines, Serial No. 247,632, filed on even date herewith. li/.iachines of this type are adapted for grinding cylindrical bodies orother bodies which are circular in cross section but which hav machine embodying the invention is provided with a broad faced wheel having a width equal to or exceeding` the length of the work to be ground.

Une of the objects of the present invention is to provide an improved means for r0- tating the work during grinding'. Another ohject ofthe invention is to provide improved n eans for controlling and directing the de livery of water to the grinding rone.v An other object of the invention is to provide. in combination with other features,improved means for dressing the grinding wheel to any desired contour. Further objects of the invention will be apparent from the following specificationr and claims.

In the accompanying drawings I have shown the embodiment of the invention which l now deem preferable, but it will be understood that the drawings are to be considered as merely illustrative and are not to be construed as defining or limiting the scope of the invention, the accompanying claims being relied upon for that purpose:

Of the drawings:

Fig. l is a front elevation.

Fig. 2 is a plan view. Y

Fig. 3 is an end view on an enlarged scale talren from the left, the motor being removed.

Fig. 4 is an end view on the same scale as Fig. 3 taken from the right.

Fig. 5 is a vertical sectional view on the saine scale as Figs. 3 and 4 taken along the line 5--5 of Fig. 1.

Fig. 6 is a fragmentary vertical sectional view taken along the line 6--6 of Fig. 3.

Fig. 7 is a fragmentary view similar to Specification of Letters Patent.

Patented May 16, 1922. Serial N o. 247,634. Y

thev upper right-hand part of Fig. 6 but showing a modified arrangement of parts.

l1 1g. 8 is an enlarged front view showing the mechanism ing frame. l

Fig. 9 is a fragmentary sectional view taken along the line 9-9 of Fig. 5.

Fig. 10 is a fragmentary sectional View taken along the line 10-10 of Fig. 3.

J Fig. 11 is a fragmentary sectional view taken along the line 11-11 of Fig. 10.

Fig. 12 is a fragmentary rear view, partly in section and partly in elevation, showing the headstocl: andl parts of the gearing associated therewith.

Fig. 13 is a vertical sectional view taken along the line 13-13 of Fig. 12.

Fig. 14 is a sectional view taken alonof the broken line lll-laof Fig. 13. b 1 Fig. l5 is avscctional view taken along the oroken line lo-l5 oi Fig. 13.

Fig. 16 is a detail sectional view taken along the line EIS-16 cf Fig. la.

Fig. 1.7 is a fragmentary sectional view taken along the line `1?-14' of Fig. 13.

n Fig. 18 is a detail View taken along-'the line .i3-13 of Fig. 10.

Fig. 19 is a detail view showing the mechanism for moving the headstoclr center.

Fig. 20 is fragmentary sectional view taken along the line 20*20 of Fig. 5.

2l is a detail view of the former.

5*.. machine embodying the invention com- Qrises a main frame 1 upon which is mounted a grinding wheel 2 rotatable about a longitudinal horizontal axis. rifhe wheel has a broad working face which preferably extends the full length of the work to be ground. Mechanism is provided for rotating the wheel, this consisting in the present instance of an electric motor 3 mounted on an extension fl of the main frame. The machine is primarily intended for grinding work which is circu lar in cross section. hut its use is not necessarily limited to the grinding of work of this character. There is provided a suitable work support for holding the worlr to be ground, such as shown at A. Preferably the work support comprises centers carried respectively, by a headstock 5 and a tailstocl` 6. which are longitudinally adjustable along horizontal ways formed on a table 7. Means is provided for causing relative approaching and separating movements ybetween the work for swinging the work carrysupport and the wheel for initially bringing the work into contact with the wheel and for feeding. In order to provide a rigid support for the wheel which will hold it against vibration, and in order that the wheel may be directly connected with the motor l prefer to mount the wheel in fixed bearings and to move the work support toward and from the wheel. lVhen the wheel is thus mounted the table 7 is carried by a frame 8 which is moved to bring the work into or out of operative engagement with the wheel. Preferably'this frame is pivoted near its bottom to the main frame 1, as, for instance, by means of a bearing shaft or trunnion 9, which extends from one end of the frame to the other.

Having now briefly outlined some of the more important elements of the machine, l will now proceed to a more detailed description of the several parts.

As shown most clearly in Fig. 6, there are, provided. two bearing brackets 11 and 12 which project upward from the main frame 1 and which carry a rotatable spindle 13. Secured to this spindle, by any usual or preferred means, and positioned between the bearings, is the aforesaid grinding wheel 2. rlhe motor 3 is mounted with its drive shaft 14 in alinement with the spindle 13, and carried respectively by the spindle 13 and the shaft 14 are flanges 15 and 16. The f'langes are provided respectively with oppositel, projecting pins 1T' and 18 and an endless flex` ible belt 19 is vlaced back and forth over the pins 1T and 1S. The mechanism which l have described constitutes a yieldable Hexible coupling between lthe shaft 14: and the spindle 13.

l provide a suitable surrounds the grinding wheel. As concerns many of the features f the invention the guard can be of any usual or preferred construction, but l prefer a guard such as is shown in the drawings and will be described.

The guard is constructed in a manner to provide a high tensile strength which will enable it to resist breakage in case of breakage of the grinding wheel. PreferabljY this tensile strength is provided by forming the sides of the guard of sheet metal. By preference in order that the guard may be easily opened to permit access to the wheel it is formed witI a top section which is readily separable from the bottom section.

is illustrated, the lower section comprises two similar oppositely disposed cnd plates 2U and 21 positioned adjacent the bearing brackets 11 and 12 respectively. These plates 2() and 21 are connected by rods 22 which extend through suitable apertures in the plates, these apertures being spaced at intervals along` the outer edges. Preferably, as shown in Fig, 5, the portions of the rods between the plates are square. A double guard which partly sheet metal casing 23 is secured to these rods, this casing preferably consisting of a single sheet of metal whichrextends from the rear and engages the outer surfaces ofthe several rods and is looped around the front rod. From this front rod the sheet extends rearward engaging the inner surfaces of the rods. The sheet metal is secured to the rods in any suitable manner, as, for instance, by means of rivets 24 extending through apertures in the rods.. Preferably the end plates 20 and 21 areprovided with grooves,v as shown in Fig. 6, into which the edges of the sheet metal 23 extend, thus making a tight joint. Preferably the lower section of the guard is provided with a drain aperture as shown at 23a.

The upper section of the guard is constructed similarly to the lower section, this upper section comprising end plates 25 and 26 which are connected by rods 27. Secured to the rods 27 is a sheet metal casing 28 similar to the sheet metal easing 23 already de-v scribed. The two sections of the guard are separated at their front edges, as shown, to provide access to the wheel, but their rear edges are closely adjacent. Preferably the sheet metal of the two casing sections is extended, as shown at 29 and 30, to overlap and prevent the escape of water between the two sections.

In order that the guard may be moved to accommodate wheels of different diameters and to compensate for changes in the diameter of a single wheel due to wear, l provide means whereby both sections of the wheel may be moved backward or forward.

The end plate 20 of the lower section of the guard isprovided with apertured ears 31 and 32 which carry a horizontal pin 33. The pin extends through a bearing aperture in the body part of the bearing bracket 11. The opposite end -plate 21 is provided with a horizontal lug 34 which fits between lugs 35 carried by the bearing bracket 12 and a latch 36 pivoted to the bearing bracket at 37. As shown in Fig. 3, the length ofthe pin 33 lbetween the ears 31 and 32 is considerably greater than the width of the bearing bracket 11, thus permitting the pin to slide inthe aperture. The construction at the right-hand end also permitsforward and backward movement and the entire lower section can thus be adjusted. After adjustment the section can be locked in adjusted positionV by means of a screw 33Ll which engages the pin 33 and by means of a screw 33 which engages the latch 36 and forces it into firm engagement with the lug The upper section of the guard is preferably supported entirely independently of the lower section. As illustrated extensions 39 and 40 are formed respectively on the bearing brackets 11 and 12. The plates 25 and 26 are provided' respectively with lugs 4l and 42 which rest on these extensions and are capable of sliding movement therealong. Each of the lugs is provided with a T-bolt 43 which engages a T-slot 44 in the corresponding extension. By means of these T- bolts the upper section of the guard can be secured in place after adjustment. lt will be noted that by removing the nuts on the T- bolts 43 the entire upper section of the guard is loosened Vso that it can be freely removed to expose the wheel and to permit the wheel with its spindle to be taken out if necessary.

Preferably interlocking means are pro` vided for insuring the uniform movement of the two guard sections forward and backward. As illustrated7 this interlocking means comprises projections 45 on the upper plates 25 and 2G, these projections extending into grooves 4G in the lower plates 20 and 2l.

For convenience in moving the guard forward or backward, there are preferably pro vided two handles 47. Each of the handles is constructed in two parts formed respectively on the upper and lower plates of the guard.

ln order that water may be delivered to the grinding wheel and uniformly distributed along its entire length, l provide a se` ries of nozzles 4 8 as shown clearly in Figs. 2 and 6. It will be observed that these noz zles are provided with elongated discliarge orifices and that the nozzles are placed close together as to provide a substantially conN tinnous .sheet of water from one end of the wheel to the other. These nozzles are connected. by means of short nipples 49, with a manifold which extends the entire length of tie wheel. l

li a wheel 2 is to be used which is shorter than the full length for which the machine is designed, one or more of the nozzles 4S, at either or both ends, may be removed as 'indicated in Fig. 7. fin this case the corresponding nipples 49 are closed bymeans of caps 5l;

ln order that the stream of water may be confined and directed more accurately to the grindinfil nozzle .l with a sheet metal guide rlhis is turned inward at its lower edge as shown in 5. The guide is held in place by means of a screw 53 which extends through a vertical slot 54, tl'ius permitting vertical ad justment.

The manifold 5() is supported by means of screws which extend respectively through slots 56 56 formed in brackets 57. carried respectively by the end plates 25 anc 26 of the guard. rl'hese slots permit the manifold with the nozzles to be moved circumferentially of the wheel. the nozzles can be kadjusted. in accordance with the diameter of the work being ground. Avfi'er adjustment the manifold with the nozzles ,can be clamped in adjusted position by zone, l preferably provide each.

lnthis wayk tightening the screws 55. by means of handles 58.` 58 secured to the ends thereof. inasmuch as the nozzles 48 are carried by the guard, it will be clear that they will be moved forward or backward to accommodate wheels of different diameters when the guard is moved, l/Vhen the upper section of the guard is taken olf to expose the wheel the manifold and the nozzles are carried with it.

llVater is supplied to the manifold 50 through two pipes 59 lwhich are connected by means of flexible hose sections GO, 60 with a supply pipe 6l. Water may be supplied to the pipe 6l from any desired source. but l prefer to provide a pump which constructed and connected as a permanent part of the machine. .es illustratedn the extension 4 of the main frame which carries the motor 3 is constructed in the form of a tank arranged to receive the water which discharged from the wheel. For guiding the 'water into the tank the main frame is provided with edge flanges G2, 62. Positioned in the tank in a pump which is preferably of the centrifugal type. 'The rotor 63 of the pump is positioned in a casing 4 and is connected with a vertical drive shaft which carries at its upper end a belt pulley 66. A belt pulley 67 is mounted on the motor shaft 14 and a belt GS passes over and around the. two pulleys @Gund 67 to transmit power from the frame to the latter. Suitable idler pulleys 69. G9 are provided forguiding the belt. The discharge side of the pump connected by means of ai pipe 70 with the aforesaid supply pipe 6l. By means of this coistruction water may be supplied under proper pressure .to the manifold 50 and to the nozzles whenever the machine is in operation.

By preference. l provide means whereby the operator can readily control the flow of water. For this purpose I provide valve 7l in the pipe 6l. The valve has an opera ing lever 7 2 to which is pivotally connected a link 73. Extended from the front of the machine to the back near the bottom is a rock shaft 74. At its rear end the rock shaft is provided with an arm S connected with the lower end of the link 73. At its front end the rock sha-ft is provided with a double foot treadle 76 by means of which the shaft fau be turned in either direction to open or close the valve and start or stop the flow of water.

As already statedE the machine is provided with a swinging frame 8 which carries the work. The fra-nie is provided at its ends with two large depending lugs 77 and 78 which are connected with the aforesaid trunnion 9, rlhe trunnion is seated'in suitable bearing apertures in the main frame. The swinging frame 8 is preferably of skeleton construction, having a thin front plate 79 which joins near its top with a horizontal plate 80. A plate or apron 81 extends diagonally downward from the inner edge of the plate and overlaps the front liange 62 on the main frame, as clearly shown in Fig. 5. This apron assists in preventing the escape of water and serves to guide it downward into the space between the flanges 62. The table 7 is supported above the plate 80 and between the table and the plate there is provided. a long clear open space for a purpose which will presently appear.

The table 7 is provided with longitudinal ways 82 and 83. The headstock 5 is slidably mounted on the ways 82 and 83 and is adapted to be held in place and clamped by means of a bolt 84 having an enlarged head 85 engaging the lower inner side of the way 83. As shown most clearly in Fig. 10, the body of the headstock carries a longitudinal bushing 86 which is fixed against relative movement. Mounted in the bushing 86 is a sleeve 87 which carries a center 88 adapted to engage and support one end of the work. rThe sleeve 87 is preferably longitudinally slidable and is held 'against rotative movement by means of a pin 89 which enters a slot 90 in the bushing 86. The wall of the body part of theheadstock is provided with an aperture through which the pin 89 may be put in place or removed, this aperture being normally closed by plug 91.

The headstock is provided 'with power operated means for rotating the work. Preferably this comprises a gear 92 rotatably mounted on the bushing 86. The hub of the gear is extended toward the right and is provided with an annular groove into which fits a shoe 93 serving to hold the gear in place. The hub of the gear is also eX- tended toward the left and carries a pin 91 adapted to engage a dog B secured to the work A. The gear 92 meshes with a gear 95 mounted on a rotatable sleeve 96. Preferably a. plate 97 is provided for covering the two gears. The sleeve 96 is rotatable in a suitable bearing aperture in the body of t-he headstock and is splined to a longitudinal shaft 98. Mounted on the end of the table 7 is a housing 99 into which the shaft 98 extends having bearings at 100 and 101. The splined connection between the shaft 98 and the sleeve 96 permits the headstock to be adjusted along the table Without vinterfering in any way with the power connection.

Rotatably mounted in the housing 99 is a drive shaft 102. This shaft at its left-hand end projects outside of the housing and carries a belt pulley 103. As indicated in Fig. 1, the trunnion 9 is provided at its lefthand end with an extension 104 upon which is rotatably mounted a sleeve 105. This sleeve carries a belt wheel 106 which is in register with a belt wheel 107 on the grinding wheel spindle 13. A belt 108 passes over and connects these two pulleys. Also connected to the sleeve 105 is a belt pulley 109 which is in register with the belt pulley 103 on the shaft 102. A belt 110 passes over and connects these two pulleys. lt will be clear that by means of this construction power is transmitted from the spindle 13 to the shaft 102, the construction being such that the frame 8 may be swung without interfering in any way with the power con nection.

Independently rotatably mounted on the shaft 102 are two differently diametered gears 111 and 112. Associated respectively with the gears 111 and 112 are clutches 113 and 114 by means of which either of the gears may be operatively connected with the shaft. Rigidly connected with the shaft is a hub 115 and connected respectively with the gears are annular flanges 116 and 117 which extend over and partly enclose the hub. As shown more clearly in Fig. 16, an expansible ring 118 is located in the space between the hub 115 and each of the flanges, as for instance the flange 117. A knuckle lever 119 is positioned within a slot 120 formed in the hub and the end portion of the lever extends into the space between the ends of the ring. Mounted in a radial aperture in the hub 115 is a plunger 121 adapted to engage the lever 119 and move it in such a manner as to expand the ring into frictional engagement with the flange 117, thus clutching the flange together with the attached gear to the shaft. The shaft 102 is provided with a longitudinal central aperture in which is slidably mounted a rod 122, this rod having longitudinal grooves 123 into which project the beveled ends of screws 124-. The plungers 121 extend respectively into the aforesaid grooves 123 and are beveled at their ends and are adapted to be engaged respectively by the ends of the screws 124 when the rod 22 is moved longitudinally. As shown, the rod 122 is in its central or neutral position, but it will be clear that by moving the rod in one direction or the other either of the screws 124 may be engaged with the corresponding plunger 121 to expand the corresponding ring and clutch the corresponding gear to the shaft. Formed at the left-hand end of the rod 122 is an annular rack 125 which meshes with a gear 126 mounted at the inner end of a rock shaft 127. This rock shaft has a bearing in the table 7 and is provided at its outer end with a hand lever 128. By means of this lever the rock shaft can be turned to move the rod 122 in one direction or the other and thus operate the clutches. Preferably lthe lever 128 is provided with a spring-pressed plunger 129 which is adapted to be seated in one or another of holes 130 formed in the table. The plunger cooperating with these holes serves to hold the lever a finger 159 which engages the walls of an either in its central neutral position or in one or the other of its operative positions.

The gears 111 and 112 mesh respectively with gears 131 and 132 which are secured to a shaft 133 rotatable in bearings in the housing` 99. Loosely mounted on the shaft 133 are three differently diametered gears 1.34, and 136 which mesh respectively with gears 137, 133 and 139 rigidly secured to the aforesaid shaft 98. The shaftl 133 is provided with a longitudinal central aperture in which is slidably mounted a rod 149, Pivotally connected with the rod 140 is a keiY 141 which projects through a slot 142 in the shaft and is adapted to enter key ways formed in the gears 1347 135 and 136. A spring` 143 tends to press the key into engagement with the gears. Between each two adjacent gears is a ring 144 which engages the key and swings it inward when it is being moved from one gear to the next, thus prevent-ing the key from engaging two ,gears at the same time.

The rod 140 is provided with an annular rack 145 which meshes with a gear 146 on a rock shaft 147 which is shown clearly in Fig. 17. The shaft 147 is supported in a suitable bearing aperture in the housing 99 and is provided at its upper forward end with a hand lever 143. The hand lever 148 is provided with a spring-pressed plunger 149 adapted to enter notches 15() in a segment 151 carried by the housing. By adjusting the lever to seat the plunger in one or another of these notches. the key 141 may be moved into engagement with any one of the gears 134, 135 or 136.

1t will be seen that by means of the clutches 113 and 114 the shaft 133 may be driven at either of two speeds. By means of the gears 134 to 139 the shaft 98 may be driven from the shaft 133 at any one of three relative speeds. It is possible` therefore, for the operator by properly manipulating the two levers 128 and 148 to cause the shaft 98 to be driven at any one of six speeds, as desired. inasmuch as the shaft 93 serves to drive the work, the speed of the work may be changed in the manner stated.

The tailstock 6 is slidable along the aforesaid ways 32 and 83 on the table and the tailstock can be clamped in adjusted posi` tion by means of a. bolt 152 having an enlarged head 153 engaging the lower inner side of the way 169. Carried by the body of the tailstock is a sliding sleeve 154 which carries a center 155 in alinement with the center 88. The outer end of the sleeve 154 is recessed to receive a spring 156 which normally tends to move the sleeve toward the headstock. F or moving the sleeve in the opposite direction there is provided a lever 157 pivoted at 158 and prevd-ed with aperture inthe sleeve. Preferably a screw 160 is threaded into the sleeve and is provided with a knob 161. This screw is used for ejecting the center 155 when necessary.

The machine is primarily intended for use in grinding a large number of pieces of the same character and size and when it is to be so used the headstock and the tailstock are YFirst adjusted to the proper distance apart. The work to be ground is first dogged and then the dogged end is placed in engagement with the center 88. By means of the lever 157 the operator draws back the center 155 against the pressure of the spring` 156. The work is then swung into alinement with the centers and the center 155 is permitted to move under the action of the spring into engagement with the work. In this way the work is engaged by the centers wit-h predetermined pressure.

It is frequently possible to rely entirely upon the spring 156 for holding the center 155 in engagement with the work during grinding. It sometimes happens. however, for work requiring a heavy pressure against the grinding` wheel. that it is desirable to firmly lock the tailstock center against any possible backward movement. A suitable locking mechanism is shown in Fig. 18. As illustrated, the tailstock casting is provided with an aperture 162 which intersects the aperture in which the sleeve 154 is posi,- tioned. Slidable within the aperture 162 Aare two slices 163 and 164 which are adaptedv to engage the sleeve 154 as shown. A screw .165 has engagement with these two shoes and carries a handle 166 by means: of which it may be turned to draw the shoes together. Thus the operator, by turning the handle 166 can move the two shoes toward each other and force them into engagement with the sleeve 154` thereby locking the sleeve and the center in adjusted position.

From the description that has already been given it will be understood that in the preferred embodiment of the invention the wheel is fixed against bodily movement and that the work is moved by means of the swinging frame into and out of engagement with the wheel. F or swinging the frame to effect feeding 1 provide a draw bolt or screw .167 which extends through an aperture in the front 'of the frame. This screw engages a threaded nut 163 carrying a. hand wheel 169. The inner end of the screw is horizontally pivoted to a bracket 170 carried by the main frame and projecting into the space between tho plate 79 and the apron 81 of the swinging frame. The apron serves to1 prevent water from reaching the pivot for the screw. Surrounding the nut 168 is a sleeve 171 which is supported by pivot studs 172 vextending inward from opposite sides ef the aperture in the swinging frame, as

shown in Fig. 9. Suitable means is provided for connecting the threaded nut 168 and the hand wheel 169 with the swinging frame so that rotative movement of the wheel will serve to move the frame forward or backward on its pivotal axis as required. The operator, by turning the hand wheel 169, can change the position of the frame as required to move the work into or out of engagement with the grinding wheel and to feed the work during the grinding operation. Preferably, in order that the amount of feed may be accurately observed, there is provided a ring 173 which has frictional engagement with an annular fiange on. the hand wheel. The ring 173 carries a pointer 174 which cooperates with a scale 175 on the periphery of the wheel. The ring 173 also carries a finger 176 which is adapted to engage a stop 177 which projects outward from the swinging frame. In practice7 the operator turns the hand wheel in the clockwise direction until the work is brought into contact with the wheel and is reduced to the required size. In turning, the nger 176 comes into Contact with the stop 17 7 and thereafter the ring 173 slips on the flange of the hand wheel and remains stationary. When grinding is completed the wheel is turned in the counterclockwise direction to remove the work from contact with the wheel and the finished work is removed. When a new piece is put in place to be ground the operator again turns the hand wheel in the clockwise direction until the finger 176 again engages the stop 177. The engagement of the finger with the stop constitutes notice to the operator that the work is ground approximately to the required size. If it is found that because of wear of the wheel or for some other reason further grinding is required, this can be effected by still further turning the hand wheel. the amount of turning being measured by the graduations of the scale 175.

As already stated, the grinding wheel 2 extends substantially the entire length of the work, and for this reason it is difiicult for the operator to remove the finished work and put a new piece in place when the work is close to the wheel. There is danger that the operator will accidentally engage the work with the wheel in putting it in or taking it out and thus mar it7 and there 1s further danger that he will allow his hands to contact. with the wheel. thus seriously injuring himself. Tn order to avoid these difficulties. I have provided means whereby the swinging frame may be moved quickly through a considerable angle to remove the axis of the centers from the wheel a distance sufficient to enable the operator yto put the work in place and remove it with entire safety.

With this end in view the connection be1 tween the nut 168 and the sleeve 171 preferably comprises means whereby:n relative movement may ae effected without turning the nut. In the preferred embodiment of the invention, 1 provide a cam collar 178 which rotatably and relatively slidably mounted on the sleeve 171 and which is provided with a handle 179 by means of which it may be turned. The colla-r 178 at its outer end is associated with the hand wheel 169. a ball bearing 180 preferably being` interposed. At its inner end the collar 178 is provided with two oppositely positioned similarly formed cam surfaces 181. These two surfaces respectively engage rollers 182 carried by the aforesaid studs 172. llfhen the cam collarl 17,8 is in the position shown in Figs. 5 and 8 the highest points of the cam surfaces are in engagement with the rollers. and in this way the swinging frame is supported in its normal operative position. y By moving the handle 179 to the position indicated by dotted lines in Fig'. 8. the rollers will be made to travel relatively downward along the cam surfaces 181, thus preventing the frame to swing outward and separate the axis of the centers from the wheel. It will be noted that the -hub of the hand wheel is recessed to permit the outer end of the sleeve 171 to travel outward with= out interference when the cam collar 178 is turned. After the finished work has been taken .out and a new piece put in, the handle 179 is returned to the position shown by full lines in Fig. 8, thus restorinor the table to exactly its former position. Treferably, as shown in Figs. 3: 8 and 9, the cam collar 178 carries a stop 183 which serves to accurately limitithe movement of the collar and of the handle in the clockwise direction.

By preference the aforesaid stop 177 is not rigidly secured to the swinging frame but is pivotally mounted by means of a pivot pin 177B. This pivot pin carries a crank armv 184 having a finger 185. The finger 185 engages a cam surface 186 formed on the cam collar 178. The cam surface 186 is so shaped that it engages the finger 185 and turns the pin 17 7a to swing the stop 177 upward whenever the collar 178 is turned to swing the frame backward. Thus when t-he table is moved to its outer position the stop 177 is automatically swung upward out of the path of the linger 176. This permits the hand wheel 169 to be turned indefinitely in either direction for additional movement of the swinging frame without disturbing in any way the adjustment of the friction ring 173 and of the finger 176 carried thereby. When the .collar 17 8 is turned to swing the frame forward the stop 177 may be returned to operative position.

Preferably, in order to partly counterbalance the weight of the swinging frame and of the parts attached thereto, I provide two links 187 which are pivoted to the swinging frame at their front ends and which are engaged at their rear ends by coil springs 188. These springs serve to tension the links and to apply to the frame a force tending to swing it upward and rearward. This construction enables the operator to more easily swing the frame by means of the handle 179.

Preferably the table 7 is not fixedly connected to the swinging frame but is adjustably connected thereto so as to be capable of a slight pivotal movement about a pivot pin 189 shown by dotted lines in F ig. 1. For swinging the table about this pivot there is provided a screw 190 threaded into a nut 191 which is held against rotation and which has a tongue-and-groove engagement with a bracket 192 carried by the swinging frame. The screw extends through a bearing aperture in a bracket 193 carried by the table and is held against longitudinal movement with respect to the bracket. The screw carries a knob at 194 for turning it. By turning the screw 190 the table can be swung slightly in either direction to properly position the axis of the centers 1n parallelism with the axis of the grinding wheel; or, if required for tapered work, to position the axis of the centers at a slight angle to the axis of the wheel. Preferably the hub of the knob 194 is provided with graduations at 195 to indicate the amount of turning of the screw and thus indicate the amount of adjustment of the table. After adjustment, the table can be clamped in place by'means of bolts 196 and 197.

It sometimes happens that the surface of the grinding wheel is not entirely even and has small circumferential depressions or grooves. lhen such depressions are present they tend to cause corresponding ridges on the work and thus diminish the accuracy of the finished product. To avoid such inaccuracies I preferably provide means whereby the work may be moved a short distance longitudinally during grinding. As shown in Figs. 10, 11 and 19 a transverse rock shaft 198 is mounted in a suitable aperture in the body of the headstock. This rock shaft is provided at its 'forward upper end with a hand lever 199 and at its lower end it is provided with a cam 200. The cam 200 is positioned to engage the end of the before mentioned pin 89 carried by the sleeve 87. The operator, by turning the lever 199, can turn the cam 200 and thus move the sleeve 87 toward the tailstock. The movement of the sleeve effects the movement of the work in the same direction, the tailstock center 155 yielding against the action of the spring 156 to permit such movement. As soon as movement of the cam 200 permits, the work is moved in the opposite direction under the action of the spring 156. By this means the operator can slowly reciprocate the work longitudinally, thus entirely avoiding the possibility of ridges or irregularities thereon.

When cylindrical work is being ground, the exact extent of longitudinal movement is immaterial, but in the case of work having different diameters, as shown.y the longitudinal movement must be exactly limited in one direction or the other, or in both directions. The work may be moved far enough to bring the shoulder of the work into engagement with the shoulder of the wheel, but it will be obvious that any further movement would injure the work. In order that the longitudinal movement may be thus limited, I provide stops, which are preferably adjustable, for limiting the movement of the hand lever 199. Adjacent the lever is mounted a segment 201 having a T-slot 202 which is concentric with the axis of the rock shaft 198. Adjustably mounted on the segment 201 and held in place by bolts entering the slot 202, are two stops 203 and 204. The stop 208 is adapted to be engaged by a lug 205 formed .integrally with the lever. The stop 204 is adapted to be engaged by the end of a micrometer screw 206 carried by the lever. The screw carries a knob 207 provided with a scale 208. It will be seen that hy means of the stops 203 and 204 the movement of the lever 199 can be limited Aso as to stop the movement of the work in either direction at any desired point. The micrometer screw enables the operator to secure minute adjustments of the limit of movement in one direction as may be necessary when a shoulder ofthe work is to be accurately ground.

I provide suitable means in the form of back-rests for supporting the work during grinding. Preferably there are several back-rests positioned at intervals along the work. The back-rests are independently movable so that they may be properly positioned in accordance with the character of the work.

.As illustrated, each back-rest comprises a bed plate 209 which fits and is adjustable along the way `82. For clamping the bed plate 209 in position there is provided a clip 210 adapted to be pressed against the bottom of the way 82 by means of a Screw 211. A frame member 212 is providedl which is adjustable on the bed plate 209 toward and away from the grinding wheel. The movement of the frame member is effected by means of a screw 213. After adjustment the frame member can be locked by means of the set screw 214.

Projecting outward from the frame member 209 is a guide pin 215 which extends into and fits an aperture in a shoe support 216. This shoe support is slidable along the pin tongue-and-groove 215 and is provided with two shoes which engage the work. The shoe support has a engagement with the frame member at 217 which prevents it from turning on the pin. For moving the shoe support there is provided a lever 218 which is pivoted near its lower end to the frame member 212. The lever 218 at its lowerI end engages the inner end of a screw 219 which has threaded engagement with the shoe support 216. It will be obvious that when the lever is turned in the clockwise direction the shoe support will be forced outward along the pin 215. The position of the shoe support with respect to the lever can be changed by adjusting` the screw 219.

At the upper end of the bed plate 209 there is provided a boss 220 formed with a threaded aperture through which extends a rod 221. The upper left-hand end of the rod carries a pivot pin which extends through a slot in the upper right-hand end of the lever 218. Surrounding the rod 221 and having threaded engagement with the aperture in the boss 220 are two bushings 222 and 223. Surrounding the rod 229 and positioned. within the upper bushing 222 is a coil spring 2241. This spring abuts at its upper end against a part of'the bushing 222 and at its lower end abuts against a collar 225 secured to the rod 221. This spring tends to move the rod downward towardy the right and thus tends to swing the lever 218 in the clockwise direction and press the shoes against the work. The lower bushing 223 may be adjusted to be engaged by the collar 225 at the proper time to limit the movement of the rod 221 and thus limit the movement of the shoes.

In order that the finished work may be easily removed and new work put in place, it is desirable to provide means whereby the several back-rests may be easily and quickly withdrawn simultaneously. I provide an eccentric rock shaft 226 which is positioned adjacent the lower ends of the rods 221 and which is rotatably mounted in bearings carried by the table 7. A handle 22T is secured to the rock shaft at one end for turning it. When the rock shaft is turned by the handle it engages the rods 221 to move them rearward and upwardl` thus withdrawing the shoes from engagement with the work.

Each of the back-rests as thus far described is adapted to apply a uniform spring pressure to the work during grinding, the shoes yielding as required to permit inequalities of the work to pass. It is sometimes desirable. however, to provide a rigid support for the work which does' not permit any backward movement of the shoes. In order that such a rigid support may be secured, the frame member 212 is provided with an extension 228 which is provided with slots 229 for guiding a pin 230 carrying a roller 231. The slots 229 are provided at their upper ends with notches adapted to engage the pin and hold the roller in its upper position, as shown. lVlien the pin 230 is disengaged from the notches7 the roller 231 is permitted to move downward by gravity and to engage the upper surface of the lever 218 and prevent the movement of the lever in the counter-clockwise direction. The lever can freely move lin the clockwise direction to advance the shoes but the roller moves downward at each such movement of the lever and prevents it from being turned in the opposite direction.

The surface of the grinding wheel 2 must conform to the shape of the work to be ground. For cylindrical or uniformly tapered work the wheel is preferably cylindrical throughout. For work other than straight tapered work which varies in diameter the wheel must be dressed to a contour corresponding to the contour of the work. In order that the dressing of the wheel, whether for cylindrical grinding or for contour grinding.y may be easily and accurately effected, I provide a special wheel dressing mechanism which constitutes a permanent part of the machine. The wheel dressing mechanism by itself is not claimed as a part of this invention, being covered by my copendmg application for wheel dressing mechanism, Serial No. 247,637 filed on even date herewith.

Formed in the bottom of the table 7 is a longitudinal dovetailed recess which forms a guideway. Fitted in this recess for sliding movement is a slide 232. The slide 232 carries a wheel dressing tool 233 of any usual or preferred construction. The slide is adapted to be moved longitudinally of the table in the space between the bottom of the table and the top of the plate 80. Then it is so moved the tool 233 travels along the surface of the wheel to properly dress and true it. In order that the wheel may be dressed te any desired contour the tool 233 is net carried directly by the slide 232 but is mounted on a second slide 2341c which is transversely movable with respect to the slide 232. I provide means whereby the slide 234 may be moved forward 0r backward simultaneously with the longitudinal movement to enable the tool to dress the wheel to the required contour. This means comprises a former plate or bar 235 (shown in detail in Fig. 21) which is secured in a rabbet formed, at the lower front edge of the table. The front edge of the former is shaped. to conform to the required contour of the wheel and it will be understood that the former 235 can be removed and another founer substituted having a different contour. The slide 234 is provided with means for engaging theformer 235, this means preferably comprising a bracket 236 projecting upward from the front end of the slide and a roller 237 carried by the bracket. A coil spring 298 is provided for pressing the slide forward and holding the roller in engagement with the former 235. Preferably there is a. cover secured to the table and er;- tending over the former and the rolle-r to protect them and exclude dirt. .f-is shown the aforesaid bracket 193 is formed to constitute this cover.

In order that the wheel may be given eX- actly the same contour as the former, it is necessary for the point of the tool to move in a plane which passes through the axis of the wheel. As shown in Fig. 5, the swinging frame 8 is so positioned that the slide 234 is horizontal, the point of the tool 233 being at the same level as the axis of the wheel. After the wheel has been worn to a` smaller diameter, the tool 233 must be moved rearward in order to engage the wheel. This rearward movement might be effected by swinging the frame 6, but obviously this swinging movement would incline the slide 234 so that the tool. 233 would move in a plane not passing through the wheel axis. The result would be that the contour of the wheel would not conform exactly to the contour of the former. When the required contour is such that the variations in the diameter of the wheel are slight. the inaccuracy resulting from the movement above described would probably be so small as to be negligible; but, in order that the machine may be adapted for the 'dressing of wheels to contours causing widely different diameters, I prefer to provide means whereby the tool 233 may be adjusted without moving the frame 8 or inclining the slide 2234. As illustrated, the tool 233 is connected with the slide 234 by means of a second transverse slide 239; This slide is movable under the control of a screw 240 provided with a handle 241. Bymeans of the slide 239 the tool 233 can be moved to compensate for differences in diameter of the wheel without moving the frame 8 in such a wayv as to incline the slide 234.

it will be understood that it is necessary to keep the slide 234 horizontal only when the wheel is being dressed to different diameters in accordance with 4a given contour. When the wheel is being dressed to a simple cylindrical form the exact'position oit the slide 234 is immaterial. Even in this case, however, the supplemental slide 239 is advantageous as it enables the dressing tool 233 to be adjusted in accordance with worlr of different diameters. It will be seen that the work support must occupy different positions in accordance 'with the diameters of the work and that by means of the slide 239 the dressing tool can be adjusted so as to lie in close proximity to the wheel, notwithstanding the position of the work support.

ed engagement therewith. It will be seen that when the screw is turned the slide will be moved longitudinally, carrying with it the slides 284 and 239 which are at the same time moved forward or backward under the control of the former 235. I prefer to provide power mechanism for rotating the threaded shaft or screw`242, this mechanism preferably being associated with the mechanism in the housing 99 for rotating the work. n

Mounted on the shaft 102, preferably adjacent the gear 111, is a gear 243 which meshes with a gear 244 secured to a shaft 245 rotatable in a bearing in the housing 99. Rotatably mounted on the shaftY 245 are three differently diametered gears 246, 247 and 248 which mesh respectively with gears 249, 25() and 251 rigidly secured to a shaft 252 rotatable in bearings in the housing. The shaft 245 is provided with a central longitudinal aperture in which is mounted a rod 258 to which is pivoted a key 254 projecting through a slot 255 in the shaft. This key is adapted to enter keyways formed in the gears 246, 247 and 248. A spring 256 tends to swing the key outward into engagement with the gears. It will be seen that when the rod 253 is moved longitudinally the key may be engaged with any one of the gears. Between each two adjacent gears is mounted a ring 257 which serves to swing the key inward when it is being moved and thus prevents it from being engaged with two of the gears at the same time. The-rod 253 is provided at its right-hand end with an annular rack 258 which meshes with a gear 259 on a rock shaft 260. This rock shaft is suitably mounted in the table 7 and is provided at its outer end with a hand lever 261. The hand lever carries a spring-pressed plunger 262 which is adapted to engage one or another of three notches 263 formed in a segment 264 carried by the table. By moving the lever to bring` the plunger into register with one or another of the notches the key 254 may be engaged with any one of the gears 246, 247 or 248, as desired.`

Mounted in suitable bearings in the housing 99 is a shaft 265 which is in alinement with the threaded shaft 242. These two shafts are connected by a suitable coupling 266. Loosely mounted on the shaft 265 are two differently diametered gears 267 and 268. The gear 267 meshes with a gear on the shaft 252 which may be the aforesaid gear 250, as shown. The gear 268 meshes with an idler gear 269 which in turn meshes 

